/*
 * Copyright (C) 2011-2014 GUIGUI Simon, fyhertz@gmail.com
 *
 * This file is part of libstreaming (https://github.com/fyhertz/libstreaming)
 *
 * Spydroid is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * This source code is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this source code; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

package net.majorkernelpanic.streaming.rtp;

import java.io.IOException;

import android.util.Log;

/**
 * RFC 3267.
 * <p>
 * AMR Streaming over RTP.
 * <p>
 * Must be fed with an InputStream containing raw amr nb
 * Stream must begin with a 6 bytes long header: "#!AMR\n", it will be skipped
 */
public class AMRNBPacketizer extends AbstractPacketizer implements Runnable {

    public final static String TAG = "AMRNBPacketizer";

    private final int AMR_HEADER_LENGTH = 6; // "#!AMR\n"
    private static final int AMR_FRAME_HEADER_LENGTH = 1; // Each frame has a short header
    private static final int[] sFrameBits = {95, 103, 118, 134, 148, 159, 204, 244};
    private int samplingRate = 8000;

    private Thread t;

    public AMRNBPacketizer() {
        super();
        socket.setClockFrequency(samplingRate);
    }

    public void start() {
        if (t == null) {
            t = new Thread(this);
            t.start();
        }
    }

    public void stop() {
        if (t != null) {
            try {
                is.close();
            } catch (IOException e) {
                Log.e(TAG, "IOException happened", e);
            }
            t.interrupt();
            try {
                t.join();
            } catch (InterruptedException e) {
                Log.e(TAG, "Thread interrupted exception happened", e);
            }
            t = null;
        }
    }

    public void run() {
        int frameLength, frameType;
        long now = System.nanoTime(), oldtime = now;
        byte[] header = new byte[AMR_HEADER_LENGTH];

        try {
            // Skip raw amr header
            fill(header, 0, AMR_HEADER_LENGTH);

            if (header[5] != '\n') {
                Log.e(TAG, "Bad header ! AMR not correcty supported by the phone !");
                return;
            }

            while (!Thread.interrupted()) {
                buffer = socket.requestBuffer();
                buffer[rtphl] = (byte) 0xF0;

                // First we read the frame header
                fill(buffer, rtphl + 1, AMR_FRAME_HEADER_LENGTH);

                // Then we calculate the frame payload length
                frameType = (Math.abs(buffer[rtphl + 1]) >> 3) & 0x0f;
                frameLength = (sFrameBits[frameType] + 7) / 8;

                // And we read the payload
                fill(buffer, rtphl + 2, frameLength);

                //Log.d(TAG,"Frame length: "+frameLength+" frameType: "+frameType);

                // RFC 3267 Page 14: "For AMR, the sampling frequency is 8 kHz"
                // FIXME: Is this really always the case ??
                ts += 160L * 1000000000L / samplingRate; //stats.average();
                socket.updateTimestamp(ts);
                socket.markNextPacket();

                //Log.d(TAG,"expected: "+ expected + " measured: "+measured);

                send(rtphl + 1 + AMR_FRAME_HEADER_LENGTH + frameLength);
            }
        } catch (IOException e) {
            Log.e(TAG, "IOException happened", e);
        } catch (InterruptedException e) {
            Log.e(TAG, "Thread interrupted exception happened", e);
        }

        Log.d(TAG, "AMR packetizer stopped !");
    }

    private int fill(byte[] buffer, int offset, int length) throws IOException {
        int sum = 0, len;
        while (sum < length) {
            len = is.read(buffer, offset + sum, length - sum);
            if (len < 0) {
                throw new IOException("End of stream");
            } else sum += len;
        }
        return sum;
    }
}
